Field of the Invention
The present invention relates to a toner for developing an electrostatic image.
Description of the Related Art
A method of visualizing image information via an electrostatic latent image, such as an electrophotographic method, is currently used in various fields, and improvement of performance including improvement of image quality and increase of speed is required.
Increasing the speed of a copying machine or a printer means that each system of developing, transferring and fixing is speeded up. Among these systems, in order to increase the speed of the fixing system, low-temperature fixability and separability (in particular, an image with a small leading margin) of a recording medium (hereinafter also referred to as paper) are required.
Attempts have been made to improve the outmigration of wax by controlling the dispersion state of the wax in a toner particle in order to achieve low-temperature fixability and separability of paper.
Japanese Patent Application Publication No. 2011-43696 discloses a method of dispersing wax in a toner particle using a styrene/acrylic binder in an emulsion aggregation method which is a method of producing a toner in an aqueous medium.
Japanese Patent Application Publication No. 2016-70986 discloses a toner in which wax is dispersed in a toner particle and the distribution state thereof is not uniform, with a larger amount of the wax being present in the vicinity of the surface layer. In this method, since the wax easily out-migrates to the toner particle surface, the releasability is improved, so that separation of the recording medium can be expected to be improved at the time of fixing.
In Japanese Patent Application Publication No. 2017-102399, the distribution of the amount of wax present in the toner particle is set to a specific range in the toner particle surface layer region, and the ratio of the amounts of wax present in the surface layer region and other regions is set to a specific range. This makes it easy for the wax to out-migrate at the time of fixing, and it is possible to improve separability between the paper and a fixing member while maintaining a state in which the low-temperature fixability is satisfactory.